The invention relates to snowshoes, and more specifically is concerned with the freedom of movement afforded between the user's boot and a snowshoe. The invention provides for addition of some rotational freedom about a roll axis, i.e., within a frontal plane, to make more comfortable, safe and convenient the traversing of hillsides where the snowshoe cannot be planted flatly on terrain.
A considerable number of snowshoes provide for freedom of movement of the user's foot and boot relative to the snowshoe on a pitch axis, that is, a traverse horizontal axis below the boot. This aids in walking over terrain where the user naturally tends to tip the foot, toe-downwardly, as the opposite foot is advanced and as the foot is lifted and moved forward, and avoids tripping the toe end of the snowshoe in the snow. Such pivoting has been achieved by supporting the boot footbed on support straps, as in Atlas Snow-Shoe Company's U.S. Pat. Nos. 5,440,827, 5,687,491 5,699,630, and 6,256,908; and has also been accomplished with simple pivot bars, as in U.S. Pat. No. 5,946,829, for example.
When traversing a side hill path, a snowshoe user needs another degree of freedom for comfort and safety in full terrain engagement—rotation about a “roll” axis, which can be described as rotation within the frontal plane. This should be a limited freedom of movement, with spring loading effective to return the snowshoe to the normal position and to resist the roll rotation of the snowshoe more strongly as the degree of roll rotation increases. Such a freedom of movement will allow the snowshoe to tip along the roll axis when the user plants the snowshoe down against terrain which is uneven and particularly, terrain which slopes from one side to the other. The snowshoe would therefore follow the terrain and be planted more firmly, while also increasing comfort and safety to the user and reducing ankle and foot stress.
U.S. Pat. No. 5,946,829 discloses a snowshoe which is aimed at the above goal. The snowshoe has a frame of a convoluted configuration, not contiguous in a closed loop around the frame, and in which inner members of the frame near the rear turn forward to form a flexible, spring-biased mounting by frame twisting that allows some degree of torsional freedom along the roll axis, i.e., in the frontal plane. That type of snowshoe frame has some disadvantages compared to the present invention described below.